Question

2. The following data show the number of cars that arrived at a Tim-Hortons drive-through between 10:00 AM and 11:00 AM each Monday for the past 50 weeks: 1 6 5 4 2 7 5 3 4 5 3 6 6 9 6 8 4 3 3 1 2 3 3 5 7 3 4 4 2 1 8 3 3 3 5 2 8 2 5 3 6 1 1 5 8 3 2 2 5 4

(a) Construct a frequency distribution table and a relative frequency distribution of the data by hand with 9 classes and a class width of 1.

(b) Use Excel to construct a histogram based on the frequency distribution table (you can copy the data directly into excel) following the procedure outlined below.

• On your worksheet, add a new column anywhere with the data and a second column with the upper class limits in order. (Note: EXCEL needs the upper 2 class limits, not lower class limits). • Install the Data Analysis ToolPak: Click the File tab and then click Options. Select Add-Ins on the left, click Analysis ToolPak in the list on the right, and then in the Manage box, select Excel Add-ins. Click Go. Select Analysis ToolPak and click Ok.

• Click the Data tab in the top menu and click Data Analysis

• Select Histogram and click Ok. • Click the Input Range box and select the column of data

• Click the Bin Range box and select the upper-class limit column data

• Select New Worksheet Ply and Chart Output; click Ok Describe the shape of the distribution (skewed right, skewed left, bell-shaped). Submit your printout with a title and labels.

(c) What percentage of weeks had exactly three cars arrive between 10:00 AM and 11:00 AM?

(d) What percentage of weeks had three or more cars arrive between 10:00 AM and 11:00 AM?

Answer 1

By hand:

Arrange the data in ascending order and then follows the instruction as given .

By excel :

Put the data in excel.
Create a bin as shown

Go to Data and select data analysis, and click on histogram

Update the values are shown

the output will produced as followes

(c) What percentage of weeks had exactly three cars arrive between 10:00 AM and 11:00 AM?
0.24
We need to check the relative frequency of the interval 2-3 in the table

(d) What percentage of weeks had three or more cars arrive between 10:00 AM and 11:00 AM?
0.76

We need to add the relative frequency of from the interval 2-3 till the end.